Property of American Airlines Overhaul - Amazon S3...B. INSPECTION AND OVERHAUL Jack up the front...

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Overhaul

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Chapter 3: Overhaul Sept. 1995 p. 1

CHAPTER 3TABLE OF CONTENTS

CHAPTER/SECTION PAGE

OVERHAUL

I. RECOMMENDED OVERHAUL PERIODS 3 - 1 1

A. GENERAL ..................................................................................................................................... 1

B. HYDRAULIC PUMP ...................................................................................................................... 1

C. DISC BRAKE CALIPERS.............................................................................................................. 1

D. BRAKE BOOSTER PUMP ............................................................................................................ 1

E. MASTER CYLINDER .................................................................................................................... 1

F. PLANETARY REDUCTION HUBS ................................................................................................ 1

II. STEER AXLE 3 - 2 1

A. DISCUSSION ................................................................................................................................ 1

B. INSPECTION AND OVERHAUL ................................................................................................... 1

III. HYDRAULIC PUMP 3 - 3 1

A. DISCUSSION ................................................................................................................................ 1

B. HYDRAULIC (STEERING) PUMP ASSEMBLY REMOVAL: ......................................................... 1

C. HYDRAULIC (STEERING) PUMP ASSEMBLY INSTALLATION: ................................................. 1

IV. MASTER CYLINDER DISASSEMBLY AND ASSEMBLY 3 - 4 1

A. MASTER CYLINDER REMOVAL .................................................................................................. 1

B. DISASSEMBLY ............................................................................................................................. 1

C. INSPECTION AND REPAIR ......................................................................................................... 2

D. ASSEMBLY ................................................................................................................................... 2

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Chapter 3: Contents Sept. 1995 p. 2

IV. MASTER CYLINDER DISASSEMBLY AND ASSEMBLY 3 - 4 1

E. BLEEDING THE MASTER CYLINDER ......................................................................................... 3

F. MASTER CYLINDER INSTALLATION .......................................................................................... 3

V. FOUR WHEEL DISC BRAKES 3 - 5 1

A. BRAKE PAD REPLACEMENT ...................................................................................................... 11. Preparation: .......................................................................................................................... 12. Rear Caliper Removal .......................................................................................................... 13. Brake Pad Removal ............................................................................................................. 24. Cleaning and inspection: ...................................................................................................... 25. Brake Pad Installation .......................................................................................................... 46. Caliper Installation................................................................................................................ 47. Check-Out: ........................................................................................................................... 5

B. CALIPER OVERHAUL .................................................................................................................. 6

1. General Layout; Front .......................................................................................................... 62. Removal ............................................................................................................................... 63. Disassembly ......................................................................................................................... 74. Cleaning and Inspection ....................................................................................................... 85. Reassembly.......................................................................................................................... 86. Installation ............................................................................................................................ 97. Check-Out: ........................................................................................................................... 9

C. FRONT ROTOR ............................................................................................................................ 9

1. Rotor Removal ..................................................................................................................... 92. Cleaning ............................................................................................................................. 103. Inspection ........................................................................................................................... 104. Reassembly........................................................................................................................ 105. Installation .......................................................................................................................... 106. Check Out .......................................................................................................................... 10

D. BLEEDING THE DISC BRAKE SYSTEM ................................................................................... 11

1. General .............................................................................................................................. 112. Manual Bleeding ................................................................................................................. 113. Pressure Bleeding .............................................................................................................. 114. Check-Out .......................................................................................................................... 12

E. REAR WHEEL DISK BRAKE SPECIFICS ................................................................................. 12

1. Caliper Removal ................................................................................................................ 122. Rear Caliper Assembly ....................................................................................................... 13

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Chapter 3: Overhaul Sept. 1995 Section 3-1 p. 1

I. Recommended Overhaul Periods

A. GENERAL

The following overhaul periods are approximate and can vary greatly due to different operatingconditions. Units operating in extreme conditions such as high or low temperatures, long periodsof sustained operation, continued operation in sand or dust or continued exposure to sea air ormoisture require careful, regular inspections. Overhaul periods may be adjusted with time andexperience in operating this tractor. If an overhaul of a component or system is anticipated orrequired, the procedures that cover that component or system should be read and fully under-stood prior to attempting any part of the overhaul.

B. HYDRAULIC PUMP

Overhaul when internal or external leakage is evident or after 5,000 hours.

C. DISC BRAKE CALIPERS

Calipers should be overhauled if piston seizure is evident, if leakage occurs around piston bootor if uneven braking persists after troubleshooting brake lines.

D. BRAKE BOOSTER PUMP

Booster pump components (i.e. pump section and motor section) can be replaced more easilyand economically than overhauling. Refer to troubleshooting section to isolate brake boosterproblems.

E. MASTER CYLINDER

Refer to troubleshooting section to isolate problems with master cylinder. Master cylinder shouldbe rebuilt if piston gasket damage is evident and when significant brake pressure is being lostafter all other possible causes have been eliminated.

F. PLANETARY REDUCTION HUBS

Hubs should pass roll test and leak test before being deemed service worthy. Refer to FinalDrives supplement, chapter 5.Pro

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II. STEER AXLE

A. DISCUSSION

If tractor has been properly lubricated and maintained and has not experienced damage to thesteering system, the steering components will provide many hours of service without an over-haul. Should overhaul be required, follow the procedure below:

WARNING: OBSERVE ALL SAFETY PRECAUTIONS DISCUSSED IN THE SAFETY SEC-TION OF THIS MANUAL!

B. INSPECTION AND OVERHAUL

Jack up the front end of the tractor using normal jacking procedures (i.e., chock rear tires, applyhand brake, and place blocks under tractor front bumper).

Inspect the steering linkage rod for damage. Also check for wear of the linkage rod ball joints bygrasping the rod and shaking it. If the linkage rod ball joints are loose, replace the rod.

1. Bearings and Seals

Grasp the top and bottom of each tire and shake it in and out while observing the hub andspindle area to detect any wobble or looseness. If any wobble or looseness is noted in thehub and the spindle is rigid, the wheel bearings and seals should be adjusted by tighteningthe hub retainer nut. If excessive noise is experienced after adjustment, the bearings andseals should be replaced as follows:

(a) Remove the front wheels by removing the lug nuts on each wheel.

(b) Remove disc brake caliper.

(c) Remove the grease cap, cotter pin, outer hub retainer nut, nut lock and inner hubretainer nut.

(d) Grasp the hub and slide it off the axle shaft.

(e) Remove the inner and outer seals and bearings from the hub and wipe the hubinterior clean.

(f) Inspect hub interior surfaces (bearing races) for scoring. If the races are scored orworn, replace with new races.

(g) Install new bearings and seals into the hub, packing the bearings with lithium-basedgrease, and replace the hub onto the axle shaft.

(h) Replace caliper.

(i) Secure the hub with the retainer nuts and nut lock and replace the hub cap.

(j) Install the wheel.

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II. STEER AXLE

B. INSPECTION AND OVERHAUL (CONT):

2. A-Arm Bushings Removal/Replacement:

Note: This procedure written with the assumption that both sets of bushings to be changed.Spindle assemblies do not have to be removed for this procedure, however a-arms will be quiteheavy. Procedure is written as if spindles are to be left intact on a-arms.

a. Chock rear tires, jack front end of vehicle. Secure front with jackstands under frontframe.

b. Remove tires.

c. Remove tie rod. Note: Use jack stands, floor jacks or individual jack stands tosupport a-arms before disconnecting tie rod.

d. Remove calipers:

(1) Remove upper king pin cover (two bolts).

(2) Unbolt and tie-off calipers.

e. Remove lower shock bolt. Note: This bolt also holds bottom link of spring limiterchains.

f. Remove (2) main a-arm pivot bolts. Remove a-arm assembly.

g. Remove old bushings; press-in new bushings.Note that bushings are located at the tips of the U-shape. The span between the U-tips must be bridged so that arms are not bent during pressing. Rig a secure steelbridge between the arms, or contact Tug Manufacturing regarding special tooling.

h. Reassemble a-arm(s) but do not tighten pivot bolts.

i. Rotate a-arm into place, attach bottom shock bolt with chain limiter. Tightensecurely.

j. Tighten a-arm pivot bolts securely.

k. Reassemble remaining components in reverse order from disassembly.

3. Tie Rod Ends:

Grasp the sides of the wheel and shake it from side to side while observing the rod ends. Ifexcessive movement is observed in the rod connection ends, replace the connecting rodends as follows:

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(a) Disconnect the rod ends from the spindle arms, removing the cotter pins andretainer nuts.

(b) Remove the connecting rod and remove the rod end retainer clamps.

(c) Screw the new rod ends approximately 1/4 inch into each end of the rod.

(d) Install the connecting rod to the spindle arms, securing the connecting rod ends tothe spindle arms with the two (2) retainer nuts and cotter pins.

(e) With the wheels pointing straight forward, adjust the “toe-in” by turning theconnecting rod until the centerline-to-centerline distance across the back of the tiresis 0 to 1/8 inch longer than the centerline-to-centerline distance across the front ofthe tires.

(f) After the toe-in adjustment has been accomplished, install the rod end clamps,securing the connecting rod adjustment.

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III. HYDRAULIC PUMP

A. DISCUSSION

Hydraulic pump should be overhauled after 5000 hours or when internal or external leakage isevident. The hydraulic pump assembly can be divided into three main components. (Refer tofigure on page 2). Reservoir, pump section & motor. Disassemble and replace all worn ordamaged parts.

B. HYDRAULIC (STEERING) PUMP ASSEMBLY REMOVAL:

CAUTION! SIDE PANELS ARE HEAVY! REMOVE CAREFULLY

1. Disconnect battery, remove right side access panel.

2. Disconnect electrical wiring.

3. Remove (4) mounting bolts: Use long extension rachet and matching wrenches belowtractor.

CAUTION: WIPE ALL CONNECTIONS CLEAN PRIOR TO OPENING SYSTEM.

CAUTION: CAP OR PLUG ALL OPEN PORTS AND LINES.

NOTE: USE BACK UP WRENCHES ON ALL MATING FITTINGS.

4. Gently rotate pump to reveal access to hydraulic line connections.

5. Use tape to label lines (in & out).

6. Remove hydraulic lines at elbows.

7. Remove pump & reservoir assembly.

C. HYDRAULIC (STEERING) PUMP ASSEMBLY INSTALLATION:

1. Place pump & reservoir assembly into floor of right side service bin, reservoir end towardrear of vehicle.

2. Attach hydraulic lines at elbows.

3. Attach assembly to floor using (4) mounting bolts: Use long extension rachet and matchingwrenches below tractor.

4. Connect electrical wiring.

5. Top off hydraulic fluid in reservoir.

6. Replace right side access panel.

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Ref. Part Description No.No. No. Req'd

1 03142 PUMP ASSEMBLY, Gear Code 62 102625 PUMP ASSEMBLY, Gear Code 51 102650 PUMP ASSEMBlY, Gear Code 43 102624 PUMP ASSEMBlY, Gear Code 42 102629 PUMP ASSEMBLY, Gear Code 05 102659 PUMP ASSEMBLY, Gear Code 03 1

2. 02352 O-RING, Industrial (3-5/8 x 3-7/8 x 1/8) 13. 00075 PARTS KIT, Check Valve (main) 14. 02159 SEAL 15. 03766 PARTS KIT, Relief Valve 16. 03427 SWITCH, Solenoid, 12 VDC, 3-post grounded to can 1

03481 SWITCH, Solenoid, 12 VDC 3-post (coated) grounded to can 103336 SWITCH, Solenoid, 12 VDC, 3-post insulated ground 103340 SWITCH, Solenoid, 12 VDC, 3-post (coated) insulated ground 103335 SWITCH, Solenoid, 12 VDC 4-post isolated ground 103342 SWITCH, Solenoid, 12 VDC 4-post (coated) isolated ground 103467 SWITCH, Solenoid, 24 VDC, 3 post, grounded to can 103652 SWITCH, Solenoid, 24 VDC, 3 post, (coated) grounded to can 103343 SWITCH, Solenoid, 24 VDC 3 post insulated ground 103344 SWITCH, Solenoid, 24 VDC 3 post (coated) insulated ground 1

7. 01349 STRAP, Motor-Solenoid 18. 07683 SCREW, Round Head Machine 10-32 x 1/4 29. 08111 MOTOR, Electric, 12 VDC 1

08112 MOTOR, Electric, 12 VDC 108120 MOTOR, Electric, 24 VDC 1

10. 02318 BEARING, Base, motor 111. 07625 NUT, Hex 5/16-24 112. 07781 WASHER, Lock 5/16" 113. 07737 WASHER, Star 1/4" 414. 07795 WASHER, Lock 1/4" 215. 07738 SCREW, Hex Head Cap 1/4-20 x 6-1/2" 216. 02238 BRACKET, Mounting 117. 04559 BRACKET, Plate Mount 5.00" C to C 1

04560 BRACKET, Plate Mount 3.25" C to C 118. 07894 Socket Head Cap, Thread forming, torx drive, 5/16-18 x 1-1/8 219. 07717 SCREW, Hex Head, thread forming 1/4-20 x 1-3/8 220. 01134 SCREEN, Filter (suction) 121. 01209 TUBE, Filter Suction 3/8 NPT 90 Deg. 122. 01329 ADAPTER, Pump Mounting Bracket 123. 01274 TUBE, Return (1/8 NPT) 124. 06661 RESERVOIR, 4-1/2" Dia. x 8", 76 cu in usable 1

06663 RESERVOIR, 4-1/2" Dia. x 10", 102 cu in usable 106665 RESERVOIR, 4-1/2" Dia. x 12", 127 cu in usable 1

25. 06678 RESERVOIR, 5" x 5" x 10", 211 cu in usable106663 RESERVOIR, 5" x 5" x 12", 249 cu in usable 106665 RESERVOlR, 5" x 5" x 15", 306 cu in usable1

26. 01143 PLUG, Vent (plastic) 103866 PLUG, Vent, 3/8" NPT 1

27. 01482 TUBE ASSEMBLY, Downspout, return (1/4 NPT Mx F) 128. 07703 SCREW, Thread Forming 10-24 x 3/8" 6Pro

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IV. MASTER CYLINDER DISASSEMBLY AND ASSEMBLY

A. MASTER CYLINDER REMOVAL

1. Open Console door.

2. Remove brake lines from cylinder body.

3. Plug brake line ports or drain brake fluid into appropriate container.

4. Remove (2) mounting bolts and nuts.

5. Slide master cylinder off of push rod.

When it is necessary to repair the master cylinder during the warranty period, replace thecylinder as a unit instead of overhauling the cylinder with a service repair kit.

B. DISASSEMBLY

1. Clean the outside of the master cylinder and remove the reservoir cover and reservoirdiaphragm. Drain any fluid left in the cylinder. Be careful with brake fluid as it damagespainted surfaces.

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IV. MASTER CYLINDER DISASSEMBLY AND ASSEMBLY

B. DISASSEMBLY(CONT)

2. Remove the push rod boot (if equipped), from the groove at the rear of the master cylinder,and slide the boot away from the rear of the master cylinder.

3. Remove the snap ring holding the pistons in the cylinder body.

4. Remove the push rod (if equipped), and primary piston assembly from the master cylinder.Discard the piston assembly, including the boot (if equipped).

WARNING: USE LOW AIR PRESSURE TO REMOVE THE PISTON. HIGH PRESSURECOULD RESULT IN DAMAGE OR PERSONAL INJURY.

5. Using an air hose in the rear brake outlet port of the cylinder body, carefully blow thesecondary piston out of the cylinder body. Remove the return spring, spring retainer, cupprotector and cups from the secondary piston. Discard the cup protector and cups.

C. INSPECTION AND REPAIR

1. Clean all parts in clean isopropyl alcohol or Rotunda Brake Parts Washer (model 650016)or equivalent, and inspect the parts for chipping, excessive wear or damage. Replacethem, if necessary. When using a master cylinder repair kit, use all the parts provided.

2. Check all recesses, openings and internal passages to be sure they are open and free offoreign matter.

3. Inspect the hydraulic master cylinder bore for etching, pitting or rust. Replace the mastercylinder if any of these conditions exist.

D. ASSEMBLY

1. Remove the master cylinder from the vise. Check the outlet ports for brass burrs andremove, if present.

2. Dip all the parts except for the cylinder body in clean ESA-M6C25-B extra heavy dutybrake fluid or equivalent and lubricate the bore walls with brake fluid.

3. Assemble the secondary cup and 0-ring back-to-back in the grooves near the end of thesecondary piston. Assemble the cup protector, primary cup, spring retainer and secondarypiston return spring on the other end of the secondary piston.

4. Install the secondary piston assembly in the master cylinder. Wet the seals with the brakefluid and use caution when inserting the piston assemblies into the bore to prevent damageto the seals.

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5. Install the primary piston assembly in the master cylinder. Push the primary piston inwardand tighten the secondary piston stop bolt to hold the secondary piston in the bore.

6. Position the stop plate and snap ring on the primary piston. Depress the primary piston andinstall the snap ring in the cylinder body.

7. Bleed the master cylinder.

E. BLEEDING THE MASTER CYLINDER

Before installing the master cylinder on the vehicle, bleed the unit as follows:

1. Support the master cylinder body in a soft-jawed vise and fill both fluid reservoirs withESA-M6C25-A extra heavy duty brake fluid or equivalent.

2. Install plugs in the front and rear brake outlet ports. Bleed the rear brake system first.

3. Loosen the plug in the rear brake outlet port. Depress the primary piston slowly to force theair out of the master cylinder. Tighten plug while piston is depressed to prevent air fromentering the master cylinder.

4. Repeat this procedure until air ceases to exit at the outlet port.

5. Repeat steps (3) and (4) for the front brake outlet port with the rear brake outlet plugged.

6. Tighten the plugs and attempt to depress the piston. The piston will resist depression afterall air is expelled.

7. Install the cover and diaphragm assembly, being sure the cover retainer is tightenedsecurely. Remove the plugs.

F. MASTER CYLINDER INSTALLATION

1. Open Console door.

2. Slide master cylinder onto push rod.

3. Mount cylinder body using (2) mounting bolts and nuts.

4. Unplug cylinder brake line ports.

5. Attach brake lines to brake line ports.

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V. FOUR WHEEL DISC BRAKES

The following illustrations and procedures apply specifically to the M3 front disc brakes. Toaccomodate the specific requirements of the specialized rear end, a different brake caliper has beendesigned into the M3 rear disk brakes. In general, the following procedures can be applied to the rearbrakes as well. For specific rear brake information, refer to section E at the end of this section.

A. BRAKE PAD REPLACEMENT

Inspect the brake linings any time that the wheels are removed. Check both ends of the out-board pad by looking in at each end of the caliper. These are the points at which the highest rateof wear normally occurs. However, at the same time, check the lining thickness of the inboardpad to make sure that it has not worn prematurely. Look down through the inspection hole in thecaliper to view the inboard pad. Whenever the thickness of any lining is worn to the approximatethickness of the metal backing, all pads on the axle should be replaced.

1. Preparation:

For front service, chock rear wheels and raise front of vehicle. For rear service, chockfront tires and raise rear.

2. Front Caliper Removal

(a) Remove 2/3 of brake fluid from master cylinder reservoir.

(b) Push the piston back into its bore. This can be accomplished by using a C-clamp.

(c) Using 3/8" allen wrench, loosen and remove (2) mounting (retainer) bolts (see figure1). Lift the caliper off the rotor and position on drive axle so that the brake hose willnot support the weight of the caliper.

Figure 1

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A. BRAKE PAD REPLACEMENT

2. Caliper Removal (cont.):

NOTE: If only brake pads and linings are being replaced, omit step (d).

(d) Disconnect brake line from caliper and plug openings in caliper and line to preventfluid loss and to keep out contamination. (See Figure 2.)

(e) Inspect mounting bolts for corrosion. If corrosion is found, use new bolts wheninstalling caliper.

3. Brake Pad Removal

(a) Remove the inboard pad and spring from piston. Dislodge the outboard pad andremove from caliper.

(b) Remove sleeves from mounting bolt holes and discard. Remove the four rubberbushings from the grooves in each of the caliper ears and discard. (See Figure 3.)

4. Cleaning and inspection:

(a) Examine the piston area for fluid leaks by looking for excessive moisture aroundboot area. Check dust boot for cracks, cuts or other damage that would affect itsability to seal piston bore. If leaks are present or boot shows damage, the calipershould be overhauled. See specific section.

(b) If no defects are found, wipe clean the inside of the caliper including the four earswhere bushings are to be installed. Wipe the outside surface of the dust boot so thatwhen piston is pressed to bottom of bore, boot will fold back without coming out ofgroove.

Figure 2

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A. BRAKE PAD REPLACEMENT (CONT.):

5. Brake Pad Installation

(a) Using Delco Silicone Lube No. 179-651, lubricate new sleeves, new rubber bushings,and bushing grooves. Install rubber bushings in all four caliper ears.

Note: It is essential that the new sleeves and rubber bushings which are included ineach Delco pad kit be used, and that lubrication instructions be followed to insureproper functioning of the sliding caliper design.

(b) Use Delco Tool, J-22835, to install the sleeve. Position the sleeves so that the endtoward the pad is flush with the machined surface of the ear.

(c) Attach pad retainer clip to inboard pad lining so that spring vee is on inner arc ofpad.

(d) Install inboard pad and lining as shown. (See Figure 4.) Position outer arc of padagainst inner arc of caliper. Depress spring vee to collapse it and enable it to slipinside of piston cup. Snap pad into place.

Figure 4

(e) Clip outer pad into place opposite inner pad. Make sure that the tab at the bottom ofthe pad is engaged in the caliper cut-out.

6. Caliper Installation

(a) Position caliper over rotor and line up holes in caliper ears with holes in themounting bracket. Make sure the brake hose is not twisted or kinked.

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Figure 5

(b) Lubricate both ends of the mounting bolts with Delco Silicone Lube No. 179-651.Start the bolts through the sleeves in the inboard caliper ears and mounting bracket,making sure that the ends of the bolts pass under the retaining ears of the inboardpad. Push the bolts through to engage the bushings in the outboard caliper ears,while threading the bolts into the mounting bracket. Tighten bolts. (See Figure 5.)

(c) Torque bolts to 40.7-61.0 N-m (30-45 ft.-lbs.)

(d) Remove temporary plugs from brake pipe and fittings, connect brake pipe to caliper.Torque to 20 N-m (15 ft.-lbs.).

(e) If brass bolt and block were removed with brake pipe, unplug fittings and install boltand block using (2) new copper washers. Torque to 40 N-m (30 ft.-lbs.).

(f) Fill master cylinder and bleed hydraulic system.

(g) After installing caliper, set caliper by applying heavy force to brake pedal.

7. Check-Out:

(a) Check brake pedal for sponginess or hard pedal.

(b) Drive vehicle slowly and make several slow speed stops.

(c) Check all brake fluid line fittings and caliper areas for fluid leakage.

(d) Correct any discrepancies before returning vehicle to service.

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B. CALIPER OVERHAUL

1. General Layout; Front

Figure 6

2. Removal

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See Pad Replacement Section. Removal of the caliper for overhaul is the same as for Padreplacement except that it will be necessary to disconnect the brake hose.

3. Disassembly

(a) Move the caliper to a work bench for overhaul.

(b) Drain fluid from caliper.

(c) Remove pad and spring clip from end of piston.

(d) Before beginning caliper disassembly, thoroughly clean exterior using denaturedalcohol.

(e) Support caliper in a vise and pad caliper interior with shop cloths. Use a piece of 1x6 soft pine to prevent piston from coming out completely (See figure 7).

(f) Use just enough compressed air in caliper brake line port to force piston out.Excessive air may cause piston to be blown out of bore and become damaged.

Warning! Use of compressed air without wood block may result indamage to the piston and/or personal injury.

(g) Remove wood block. Gently work piston the rest of the way out of bore.

(h) Use a screwdriver to pry boot out of caliper as shown. Use care to avoid scratchingthe caliper bore (See Figure 8).

(i) Remove piston seal from caliper bore. Use a piece of wood or plastic (a woodentoothpick is ideal) so as not to damage caliper bore.

(j) Remove bleed valve.

Figure 7

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Figure 8


B. CALIPER OVERHAUL (CONT.):

4. Cleaning and Inspection

(a) Thoroughly clean all parts not in repair kit with denatured alcohol. Inspect caliperbore for scoring, nicks, corrosion or wear. Use crocus cloth to polish out any lightcorrosion. Replace caliper housing if bore will not clean up using crocus cloth.

(b) Carefully examine the piston exterior for scoring, nicks, corrosion and worn ordamaged surfaces. If any surface defects are detected, replace the piston.

CAUTION: THE PISTON OUTER SURFACE IS THE PRIMARY SEALING SURFACE IN THECALIPER ASSEMBLY. IT IS MANUFACTURED AND PLATED TO CLOSE TOLERANCE.REFINISHING BY ANY MEANS, OR THE USE OF ANY ABRASIVE IN THE FIELD IS NOTACCEPTABLE.

5. Reassembly

(a) Lubricate piston assembly with clean brake fluid.

(b) Position the seal in the caliper bore groove.

(c) Assemble a new boot into the piston groove so that the fold faces the open end ofthe piston.

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Figure 9

(d) Press piston assembly into caliper bore using C-clamp (See figure 9). Be careful notto unseat the seal.

(e) Position outside diameter of boot in caliper counterbore and seat with Delco tool no.J-22904.

6. Installation

Install caliper following instructions given in Pad and Lining Replacement Section. Bleedsystem.

7. Check-Out:




(d) Correct any discrepancies before returning vehicle to service.

C. FRONT ROTOR

1. Rotor Removal

(a) Rotor Removal

(1) Chock the rear tires. Jack the front wheels off the ground.

(2) Inspect the lug nuts which secure the wheel to the drive axle hub and remove.

(3) Remove the cotter pin from the hub nut and remove the nut and washer.

(4) Remove caliper assemblies. See specific section.

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C. FRONT ROTOR

(5) Slide the wheel hub and rotor off the axle.

(6) Press rotor from hub.

2. Cleaning

WARNING: NO SMOKING, FIRE OR OPEN FLAME IS PERMITTED IN AREAS WHEREALCOHOL IS BEING USED. AVOID INHALATION OF FUMES.

(a) Clean rotor with alcohol.

(b) Use lint-free cloth to dry.

3. Inspection

(a) Inspect weldments (rear only) for evidence of corrosion or cracking. Replace ifcracked or severely corroded.

(b) Inspect rubbing surfaces for evidence of corrosion, pitted or scratches. Replace ifscratched, corroded or pitted.

(c) Check the thickness and out of plane limits of the rotor. The minimum limit shouldbe .885 inches (front).

4. Reassembly: Press hub onto lugs.

5. Installation

(a) Slide the wheel hub and rotor onto the axle.

(b) Replace caliper assemblies. See Specific Section.

(c) Replace axle nut and washer and replace cotter pin. Seal with silicone sealer.

(d) Replace wheel and secure with lug nuts.

(e) Lower front wheels to the ground and un-chock rear wheels.

6. Check Out

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(b) Drive belt loader slowly and make several slow speed stops.


(d) Correct any discrepancies before returning vehicle to normal service.

D. BLEEDING THE DISC BRAKE SYSTEM

1. General

(a) If the caliper was removed for overhaul, or if the brake hose or steel line wasdisconnected for any other reason, it will be necessary to bleed all air from thecalipers and connecting lines.

(b) Prior to bleeding the system, it is important to check the master cylinder reservoir.Use hydraulic fluid, DOT 3, Extra Heavy Duty Brake Fluid to bring the level up towithin one-eighth (1/8) inch of the top.

(c) Brakes can be bled either manually or with pressure bleeding equipment.

CAUTION: FLUID WHICH IS DRAINED, FLUSHED OR BLED OUT OF AVEHICLE’S BRAKE SYSTEM SHOULD BE DISCARDED. IS NOT SAFE FORREUSE FOR ANY PURPOSE.

2. Manual Bleeding

(a) Manual bleeding requires two people; one to pump the brake pedal and another tooperate the bleeder valves. Make sure that the master cylinder is full. After thebleeder valve is opened, depress the brake pedal one full stroke, close bleedervalve, then allow the pedal to return slowly to the released position. Allowing thepedal to return too quickly may draw air into the system. Continue operating thepedal in this manner until caliper is bled. Refill the master cylinder and go on to nextcaliper.

CAUTION IN ORDER TO INSURE THAT NO AIR CAN BE SUCKED BACK INTOTHE SYSTEM, THE BLEEDER VALVE MUST BE CLOSED A THE END OF EACHSTROKE, BEFORE THE BRAKE PEDAL IS RELEASED.

(b) Check the fluid level in the reservoir frequently during the bleeding procedure.

3. Pressure Bleeding

(a) If the equipment is available, the pressure bleeding is faster, since the mastercylinder does not have to be refilled several times. Pressure bleeding equipmentmust be of the diaphragm type. That is, it must have a rubber diaphragm between

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D. BLEEDING THE DISC BRAKE SYSTEM

3. Pressure Bleeding (cont.):the air supply and the brake fluid to prevent air, moisture, oil and other contaminantsfrom entering the hydraulic system. Install the special bleeding adapter to themaster cylinder. Make sure that the pressure tank is at least 1/3 full of fluid.

Position the tank so that its hose will easily reach the adapter on master cylinder ofthe vehicle being serviced, then make the air pressure connection to the tank (20 to25 psi). Open the tank valve to bleed all air out of the hose before connecting it tothe adapter. After making this connection, open the valve when ready to beginbleeding.

CAUTION: DO NOT LIFT, MOVE OR SHAKE THE TANK AFTER AIR PRESSUREIS APPLIED. THIS MAY CAUSE AIR TO BECOME TRAPPED IN THE FLUID.

(b) Bleed front calipers.

NOTE: Pressure bleeding process may be completed more quickly by lightlytapping the brake pedal when the bleeder valve is opened. This creates pulsationsthat tend to purge air from the system.

4. Check-Out




(d) Correct any discrepancies before returning vehicle to normal service.

E. REAR WHEEL DISC BRAKE SPECIFICS

1. Caliper Removal

(a) Jack rear of tractor, remove tire.

(b) Remove (2) caliper mounting bolts.

(c) Slide caliper off top of rotor.

Note: Pad replacement can be accomodated at this point without further disassembly. Iffurther caliper service is required, refer to section A-2-(d) regarding handling of brakelines and fluid.

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2. Rear Caliper Assembly

See Figure 10 (below).

Figure 10: Rear CaliperExploded Assembly

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Property of American Airlines Overhaul - Amazon S3...B. INSPECTION AND OVERHAUL Jack up the front...

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